1. Field of the Invention
The present invention relates to a flow control device for controlling the rate of flow for various kinds of fluids. Specifically, the present invention relates to a valve mechanism of the flow control device.
2. Description of Related Art
In a valve mechanism which is used in a flow control device for controlling the rate of flow of liquefied petroleum (LP) gas, city gas, coolant for a refrigerator and an air-conditioner or liquid, a valve element is commonly driven by a solenoid.
However, a solenoid drive system controls the valve element to be in an opened state or a closed state by it being turned-on or turned-off. Therefore, when the flow rate is controlled with a high degree of precision, the operations of turning-on or turning-off are frequently repeated and thus an impact sound occurs. In addition, chattering which is inherent in a solenoid may occur and, if it occurs, a high degree of precision in controlling the flow rate is not attained.